The invention relates to a continuous casting plant with one or more tundish cars which are movable on a circular arc-shaped pathway by means of supporting or driving rollers.
In plants for the continuous casting of strands, at least two receiving means with one tundish each are necessary. Each receiving means is movable from a reserve position into a casting position and vice versa.
In their reserve positions the tundishes are charged with molten steel from a pouring ladle. In the casting position the steel is cast into the mould via a casting tube or snorkel, that is, inserted into the bottom of the tundish. It is especially important that the casting tube be in a precicely defined vertical position relative to the continuous casting mould and retain this position during the whole casting procedure. Only the height of the tundish and thus also of the casting tube is variable by means of an altitude-adjusting means, in order to allow for a change in the kinetic energy of the casting stream, if necessary.
If, during casting, the vertical position of the casting tube or snorkel changes due to a yielding of the receiving means or the supporting structure thereof, then the direction of the casting stream is also changed, which can cause the strand skin of the cast product to become uneven or even to break.
Therefore it is important to create a continuous casting plant with one or more tundish cars in which the tundishes are reliably and accurately guided during continuous operation and under changing loads and heat influences, and in which the casting tubes or snorkels, of the tundishes are accurately positioned. Furthermore the plant should be easily accessible, and the machine parts should be quickly and easily exchangeable.
Known plants with one or more tundish cars that are guided on circular arc-shaped rails do not, or do not fully, meet these demands.
U.S. Pat. No. 3,344,847, e.g., describes a device in which each tundish receiving means is guided on a circular arc-shaped pathway over a total of six running rollers. The tundish is arranged on a projecting arm. This has the disadvantage that, due to the projecting load, extremely high wheel pressures occur and complicated and expensive bearings are necessary. Moreover, the circular arc-shaped pathway carrier, which on three sides is passable by the running rollers of the tundish receiving means, is expensive and cannot be constructed rigidly enough to exclude elastic deformations; thus an accurate guiding of the tundish is not possible.
From German Pat. No. 1,963,147 a mounting of tundish launders on a roundabout arrangement for pouring ladles in continuous casting plants is known. With this apparatus a stationary center column carries pivotable arms for the ladles and also for the tundish launders, which are moveable independently of the former. The pivotable arms are connected with the tundish launders via parallel guide rods. An altitude adjustment of the tundish launders can be effected by a hydraulic piston gearing which is supported upon the respective pivotable arm and engages the parallel guide rods. For supporting the load of the tundish launders and the useful load, as well as the weight of the parallel guide rods and the piston gearing, and annular face is provided on the center column which is formed as a rail and on which a wheel rolls. This wheel is supported in the respective pivotable arm. Also in this construction, due to the unfavorably high lever ratio of the work arm to the power arm, very high wheel pressures and bearing forces arise, which lead to a fast wear and to deviations of the tundish position and require frequent re-adjustments.